neutron-ovs-agent crashes when ovs is restarted or dead

[Robin Wang]

OVS crash/restart is unpredictable, so neutron-ovs-agent should be robust enough under that situation.

But currently ovs-agent would crash when ovs is restarted or dead.

An simple reproduce procedure:

It's an compute node, built on ubuntu 14.04. Neutron code is up to date.

1. Make sure both ovs and neutron-ovs-agent is running;
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$ service openvswitch-switch status
openvswitch-switch start/running

bengo@Ctl-Nwk-Ubt-Dk-1404:/opt/stack/logs$ ps -e | grep ovs
  932 ? 00:00:02 ovsdb-server
  942 ? 00:02:04 ovs-vswitchd
29210 pts/21 00:00:00 ovsdb-client

$ ps -eLf | grep neutron-openvswitch-agent
bengo 25701 3271 25701 0 1 12:12 pts/13 00:00:00 grep --color=auto neutron-openvswitch-agent
bengo 28927 28926 28927 0 1 03:32 pts/21 00:02:35 python /usr/local/bin/neutron-openvswitch-agent --config-file /etc/neutron/neutron.conf --config-file /etc/neutron/plugins/ml2/ml2_conf.ini
=====================================

2. Stop ovs service (ovsdb-server/ovs-vswitch/..)
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$ service openvswitch-switch stop
openvswitch-switch stop/waiting
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3. Neutron-ovs-agent crashes.
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$ ps -eLf | grep neutron-openvswitch-agent
bengo 21803 9492 21803 0 1 03:42 pts/12 00:00:00 grep --color=auto neutron-openvswitch-agent
=====================================

[Robin Wang (robinwang)]

It should be an duplicated one of Bug 1296202.

Patch is proposed. See #4 in Bug 1296202 page.